Health Library

Pneumonia

What is pneumonia?

Pneumonia is an infection of one or both of the lungs. It's caused by bacteria, viruses, fungi, or chemical irritants. Pneumonia is a serious infection or inflammation in which the air sacs fill with pus and other liquid.

Lobar pneumonia affects one or more sections (lobes) of the lungs.

Bronchial pneumonia (also known as bronchopneumonia) affects patches throughout both lungs.

What are the different types of pneumonia?

The main types of pneumonia are:

Bacterial pneumonia. This type is caused by various bacteria, the most common of which is streptococcus pneumoniae (pneumococcus). It usually occurs when the body is weakened in some way, such as by illness, malnutrition, old age, or impaired immunity, and the bacteria are able to work their way into the lungs. Bacterial pneumonia can affect all ages, but those at greater risk include people who:

Abuse alcohol

Smoke cigarettes

Are debilitated

Have just had surgery

Have respiratory diseases or viral infections

Have weak immune systems

The symptoms of bacterial pneumonia include:

Shaking, chills

Low energy, fatigue, and loss of appetite

Sharp or stabbing chest pain that worsens with deep breathing or cough

Fever

Sweating

Rapid pulse

Rapid breathing

Bluish color to lips and nailbeds

Confused mental state or delirium

Cough that produces greenish, yellow, or bloody mucus

Viral pneumonia. This type is caused by various viruses, including influenza (flu). It's responsible for 1 in 3 of all pneumonia cases. Early symptoms of viral pneumonia are the same as those of bacterial pneumonia, which may be followed by increasing breathlessness, headache, muscle pain, weakness, and a worsening of the cough. Viral pneumonias may put a person at risk for bacterial pneumonia.

Mycoplasma pneumonia. This type has somewhat different symptoms and physical signs and is referred to as atypical pneumonia. It's caused by the mycoplasma pneumoniae, the smallest known disease-causing agents, and which have characteristics of both bacteria and viruses. They generally cause a mild, widespread pneumonia that affects all age groups. Symptoms include a severe cough that may produce some mucus.

Other pneumonias. These are less common and may be caused by the inhaling of food, liquid, gases, dust, or fungi.

How is pneumonia diagnosed?

Diagnosis is usually made based on the season and the extent of the illness. Based on these factors, your health care provider may diagnose simply on a thorough history and physical exam. Test may include:

Blood tests. To analyze whether infection is present and if infection has spread to the bloodstream (blood cultures). Arterial blood gas testing determines if enough oxygen is in your bloodstream.

Sputum culture. A test done on the material that is coughed up from the lungs and into the mouth. A sputum culture is often done to determine if an infection is present.

Pulse oximetry. An oximeter is a small machine that measures the amount of oxygen in the blood. To obtain this measurement, a small sensor (like a bandage) is taped onto a finger. When the machine is on, a small red light can be seen in the sensor. The sensor is painless and the red light does not get hot.

Chest CT scan. A test that takes images of the structures in the chest to see how the lungs are functioning.

Bronchoscopy. A procedure used to look inside the airways of the lungs.

Pleural fluid culture. A culture of a fluid sample taken from the pleural space (space between the lungs and chest wall) to identify the bacteria that cause pneumonia.

What is the treatment for pneumonia?

Specific treatment will be determined by your health care provider based on:

Your age, overall health, and medical history

Extent of the disease

Your tolerance for specific medications, procedures, or therapies

Expectations for the course of the disease

Your opinion or preference

Treatment may include antibiotics for bacterial pneumonia. Antibiotics may also speed recovery from mycoplasma pneumonia and some special cases. There is no clearly effective treatment for viral pneumonia, which usually heals on its own.

Other treatment may include appropriate diet, increased fluids, oxygen therapy, pain medication, and medication for cough.